1. Field of the Invention
The present invention relates to an improvement of a solid state color image pick-up apparatus provided with minute color filters in front of the light receiving face thereof to pick-up color images.
against Description of Prior Arts
Solid-state pick-up device made as a CCD, BBD, MOS device or hybrid devices thereof, which has a novel characteristic which is not possessed by the conventional picture pick-up tubes is making rapid development. The solid state apparatus, on top of smallness and light weight, low power consumption, high reliability and long life, has advantages of having no burning by image on photoelectric face and no distortion of image pattern. Accordingly, the device recently comes into wide uses in remote monitoring, application in a distance measuring, or in color television cameras using three chips, two chips of single chip. Besides, the solid state apparatus does not make distortion of pattern due to environmental magnetic field and electric field, and hence is possible to make precise measurement of position and length. In making a two-chip or single chip type color image pick-up camera, filter is bonded in front of the chip to produce separate color signals thereby; in such case, the positions of the respective colors of filter are obtained by electric means, since there is no pattern distortion like the case of conventional pick-up tube utilizing electromagnetic deflections; and therefore, the separation of color signal is possible without a particular index signal or a particular processing of signal.
It is known that, in order to make a color image pick-up camera with a single chip, an array 12 of filter having an array of colors to correspond to picture element 11 of a solid state device is bonded in front of the solid state device, as shown in FIG. 1, which schematically shows only a small fraction of the picture elements and corresponding filters, wherein C.sub.11, C.sub.12, C.sub.13, . . . C.sub.44 . . . designate element color filters of the filter 12. A color image pick-up camera is constituted in a manner that signals of the above-mentioned solid state device are then sampled or detected thereby to separate luminance signal component and chrominance signal component therefrom.
In the conventional color image pick-up camera of the abovementioned constitution, the element color filters C.sub.11, C.sub.12, C.sub.13, . . . C.sub.44 . . . have been constituted principally with primary colors, for example, red, blue and green, and therefore efficiency of light utility has been poor. That is, for example, green filter element substantially cut off other component of light, namely red component and blue component.
In another conventional color image pick-up device disclosed in the U.S. Pat. No. 3,971,065, there is disclosed that, besides chrominance element filters of red color and blue color, a further filter to produce a luminance signal is made by green element filters, but this art only discloses use of primary color filter elements whereby high efficiency of light utility is impossible.